


Beginning or End

by twoam



Category: Supernatural
Genre: Alternate Universe - Canon Divergence, Anal Sex, Angel Biology (Supernatural), Angst, Background Raphael (Supernatural), Blow Jobs, Bottom Castiel (Supernatural), Breeding, Castiel in Heat (Supernatural), Consent Issues, Creampie, Dirty Talk, Dubious Consent, Feelings Realization, M/M, Marathon Sex, Mating Cycles/In Heat, Mpreg, Nephilim, No Alpha/Beta/Omega Dynamics, Porn with Feelings, Pregnancy Kink, Season/Series 06
Language: English
Status: Completed
Published: 2021-02-28
Updated: 2021-02-28
Packaged: 2021-03-12 11:22:07
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 7,605
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29758884
Author URL: https://archiveofourown.org/users/twoam/pseuds/twoam
Summary: During Heaven's civil war, Raphael decides to try out a measure that hasn't been used against troublemakers in millenia and triggers an unplanned breeding heat in Castiel to order to break him. In desperation, Castiel turns to Dean to help him out.Or; Raphael underestimates just how stubborn Cas is, Cas is desperate on multiple axes and Dean thinks the breeding talk is just a kink and hasn't realized that a human can, in fact, knock an angel up.
Relationships: Castiel/Dean Winchester
Comments: 3
Kudos: 82





	Beginning or End

**Author's Note:**

> This is a canon divergence AU for Season 6, so Cas is at his most over-confident and maybe just a tad selfish. It's also wildy self-indulgent in several different ways and I hope you enjoy it. 
> 
> I don't know how to tag 'consent where one party likely wouldn't have consented if they had the full facts' precisely, but that happens here.

Castiel realized that he'd made a fatal mistake as soon as Raphael's hand reached out to him. He recognized the magic in Raphael's hand, even constrained by and bouncing hard against his human vessel's limits. 

No. 

But in reality, of course, yes. War was war, and fairness never came into it.

It was only a touch but it shot through Castiel. It raced straight to the deepest and most intimate part of him. His true form felt like a shadow passed through it, slicing into him. Raphael grinned at his shudder, at Castiel's human vessel recoiling at the shock of the need cutting him, sinking its sharp claws into his grace. Another finger reached towards him, to send him back to heaven and complete his humiliation and defeat. Castiel refused. 

Of course his angel blade wouldn't kill Raphael, he knew that. But it was his last resort. He refused the pain of how well he knew the exact spot to kill any regular angel now, and how he wouldn't hesitate to do it. It worked. The slide of his knife into Rafael's chest was enough to shift Raphael's weight off him, enough to give him that second he needed to escape.

He lurched to and landed states away from their encounter. Castiel sighed, leaning his back against the stucco covered wall. He could feel the heat spreading through him. But it wasn't like it should be. It wasn't like how it'd be if Raphael had triggered it in his true form. If Raphael had succeeded in blasting him back into Heaven. His human vessel, unexpectedly, did not fall immediately like his true form would, but it was starting to grow inside it.

He had five minutes, maybe ten at most. If someone wasn't fucking him in fifteen minutes, he'd be attracting every angel in the continental United States to him. Even his allies couldn't be trusted now. Raphael hadn't bound his heat to another angel who'd be his partner. He was fair game to every angel and would be completely irresistible to them. In Heaven they would all hunt him down, he would never escape. He'd heard stories of it being used as punishment long ago. A way for the archangels to make an example of exceptional troublemakers who refused to learn any other way.

Lucky him. He'd pushed Raphael to resort to such a blunt tactic. He must be desperate. Castiel would have felt some grim satisfaction at that if he couldn't feel the yawn in his stomach. It was emptying, ready to be filled with heat and desire. 

On Earth he stood a chance of escaping, but any angel that caught him here wouldn't be able to resist sending him back to Heaven to breed him properly. Crowley was absolutely out of the question. He didn't know if angel heats also affected demons and didn't want to find out. That left him only one choice. 

Dean wasn't here. He knew he wouldn't be, that Dean would have moved on. It might be weeks, even months since he last saw him. Human time slipped away from him in this war, slipped away from him now as he felt his blood racing in his veins. He took a breath, dug his cell out of his pocket and called. 

"Where are you?" He sounded normal, didn't sound strange, like he was about to go into heat. He sounded normal enough to make Dean angry with him. 

"Dude, what the hell? You've been missing for weeks and now you're all 'where are you?'."

"I'm in trouble." A pause. It dragged out, made Cas shut his eyes before he leaned his head back against the roughness of the wall. Not too proud to beg, not with what was coming. "Please tell me." It earned him a rough sigh in response. He could almost hear Dean pinch the bridge of his nose before he replied with the number of his motel room in North Dakota.

It wasn't that different from where Cas was a moment before. Cas didn't notice, didn't even hear Dean cursing as he slashed his palm open and smeared a sigil onto the room's door. It'd work to hold any angel desperate to mate with him long enough before he blasted them away. 

"Cas, seriously, what the hell is going on?" Cas turned, palm closing up under the weight of Dean's eyes, fierce but worried. He met Dean's eyes without hesitation and noticed the absence in the room. No Sam. Fine by him. It'd make this easier if it was just Dean. Cas held his gaze and ignored how he could feel heat creeping along his skin. It was starting to kick in as Dean got closer to him and ignored his personal space. 

"Raphael sent me into heat and I need someone to mate with me right now. I have about five minutes before I lose all control and try to have sex with the nearest being." Dean blinked, surprised for a moment before it was replaced by disbelief as he shook his head.

"You're fucking with me." Cas' stare didn't falter under the weight of Dean's disbelief. He was used to that, but Dean needed to understand.

"Dean." Dean cracked, threw up his hands as he turned away. 

"I'm not going to fuck you, Cas!"

"Dean." 

"Get one of your angel buddies to do it. I'm not going to do whatever freaky thing you need." 

"Dean!" Cas reached out and put his hand on Dean's arm. He didn't even manage to start to turn Dean around to face him before he felt his heat explode inside him. It burned its way and flared up inside him. The need, the want, the desperation surged through him and his knees faltered. Oh, this was much, much faster than he'd expected. Cas inhaled sharply, tried to keep his balance and focus as Dean turned around sharply to look at him. He saw the shift from anger to anger and concern again. Dean didn't understand. He had to get him to understand.

"If any angel gets hold of me in this state, even my allies, they will breed me and breed me before sending me back to Heaven to breed me more, and I will lose this war." His knees buckled but Dean's hands on his arms held him up. The touch swelled inside him, pushed at him and he could feel his human body falter from those hands. He wanted to surrender to Dean, would agree to anything if it'd get Dean to mate with him, bury himself deep in him and wreck him completely. Dean didn't still get it. It was infuriating, like it was intentional, like he didn't know that Cas wouldn't be here if he wasn't desperate. 

"You're serious? Angels breed? You can get knocked up with baby angels?"

"Yes." 

"And then?" Cas bit down on his lip. He couldn't get the words out. Couldn't explain how the pregnancy wouldn't be the problem, he could bear them without trouble. It'd be afterwards, when the new troops were safely born, when Raphael would have the time to finish making an example out of him. "Cas…" 

"I wouldn't ask this from you if there was any other way." 

"Back up a little, you're cornering me here." Cas knew his body was moving while he focused on forcing out his words. He couldn't stay still, his need was too strong. He needed to be pressed up close against Dean like this, tight against his chest. Close enough to smell him, really, really smell him. He smelt of sweat, the leather of the Impala, generic soap and a little aftershave. It added to the heat burning through him. It was unbearable, to be so close and not having Dean touching him everywhere. 

"Dean, please." His voice cracked. He met Dean's eyes and saw the hesitation and fear in them. He had to make Dean understand, make Dean agree. He pressed up even tighter against him and begged. "I need you, I need you to mate with me, I need you inside me, Dean, please." He hung on, felt his desperation leaking over and couldn't stop it, didn't want to stop it. If Dean saw it, even as he shut his eyes, he might understand. Understand exactly how much he needed Dean inside him, coming in him again and again, filling him up with his seed until he couldn't take it anymore. "Dean…"

Dean swallowed hard, and opened his eyes again. 

"They'll kill you if you go back?" Cas didn't understand why he was asking but nodded in agreement anyway. Dean looked up at the ceiling, didn't meet his eyes as he exhaled deeply through his nose. "Okay. I'll do it but after this, we are _never_ talking about it again, capiche?" The tremor of relief at Dean's agreement shook his body, washed over him like a wave. 

"Yes." It wasn't a sacrifice to say they'd never talk about it. He didn't need that, talk was cheap and Dean had agreed. Dean's agreement would spare him from getting sent back, from losing this war and leading too many to their deaths. There was only one way he could show the deep, endless gratitude he felt.

Cas dropped onto his knees in front of Dean like worship. He'd never been this close to Dean, not in a human body. He'd rebuilt every cell, pulled back together every atom of Dean's body. He knew every inch of Dean. And yet. From here, with the balding motel carpet under his knees, with his breath caught in his throat as he looked at the weave of the denim, thought of what was behind that fabric, the thighs and dip leading down, that'd guide him down the weight of Dean's cock, it was different. It made him ache, the manic edgy need to touch Dean and touch him everywhere, but just a bit awed, too, like he shouldn't touch it. Maybe this was how the humans he'd seen in front of works of art felt, the smears of colored egg worked into plaster that made a woman cry. 

Carefully and reverently he reached out. His fingers worked down his zipper, the heat of Dean under the denim hitting a switch inside him that made him need to touch more than he respected the sign that said not to touch the art. Dean exhaled sharply as he worked him out of his jeans but didn't stop him. 

"Slow down there, cowboy. Don't you even want to kiss first?" Cas looked up. Even from between Dean's thighs on his knees, fingers wrapped around Dean's cock, desperate to suck him off, he could still glare. He could still ignore any twist inside him from the suggestion. 

"This isn't funny Dean." It'd be sharper if it wasn't tainted with his lust, with how badly he needed this. Without the heat burning through him. 

"I dunno, it is a little-" Cas cut him off by taking all of his cock into his mouth in one go. Dean wasn't hard yet but Cas would get him hard and he ached at the thought of it. He could feel Dean's dick swelling in his mouth as he sucked on him, edging his tongue along the underside of his cock, teasing the head. He willed the weight to grow against his tongue and fill his mouth up with cock. He needed it, needed Dean hard and ready to fuck him, let out a needy little moan against Dean's cock at the thought. His hands moved into Cas' hair and slid through it, before fingers dug into it as he sucked harder on Dean's cock. He was fully hard now, straining against the warmth of his mouth. It felt satisfying, felt perfect with the heat and need coursing through his veins and grace. He took Dean all the way down, right to the base of his cock with his nose pressed up against his pubic hair, as Dean swore and his hips strained against Cas. 

He looked up, saw Dean had his eyes shut, lips parted as Cas swallowed around him. His cock ached seeing him like this. Didn't seem to matter that it was his first time as a human, his heat was guiding him through it. His heat kept that need pressing behind his teeth and cut through any concerns about doing this right. He wanted to keep going, let Dean come right down his throat, but the thought hurt too. It wasn't the right place. He needed to be bred, needed Dean to come in his ass. 

Cas pulled back, the pop his mouth made as it did sounded loud and obscene in the quiet room. He saw Dean's cock glisten, slick and wet with his spit, rosy with blood, hard and ready to mate with him. His own cock throbbed. It wasn't enough. He needed Dean in him, now. His hands shook from his desperation as he pulled Dean's jeans all the way down and swayed back onto his feet. Dean's hands moved to hold onto him. It stopped him falling over but Cas fell deeper into his heat as the warmth of Dean's hands burnt him, needing more, more. As he steadied himself, his lust making him clumsy, Dean's hands slid up, up under his coat to slide it off his shoulders before they stopped and dropped away. Cas tried to shrug his coat off but struggled with the arms, managed to push it off before reaching for his jacket. His fingers fumbled. He couldn't focus on what he was doing, not with Dean so close but not touching him, just watching him struggle to get his clothes off instead. The clothes that were stopping him from being touched like he needed. 

There was another sigh, deep above him, and then Dean's hands were on him. Pulling at his buttons, undoing his shirt for him, fast and efficient hands pulling his clothes off him, stripping Cas. Every brush of Dean's hand against his skin sent lust crashing through him. By the time Dean got him naked, pulling down his boxers, exposing just how hard and ready the jut of his cock was, the need was physically burning him. He needed Dean's cock inside him. He needed, desperately, more than anything, his dick nestled deep in this body and filling him up. He was too desperate to play nice, to remember his strength and not shove Dean onto the bed with enough force to make the twin bed creak in protest. 

Dean protested too, a winded groan that Cas barely heard as he pushed Dean up against the headboard, right where he needed him before he clumsily, with trembling thighs, mounted Dean. The wet slide of Dean's cock against his ass drew a little huff, not enough but a start as it dragged between his cheeks with a shift of his hips. Dean, somehow, was still wearing more clothes than him. He gave the tee under his flannel a glare, offended that it was hiding Dean from him, before he grabbed it, hiked it up to expose his chest. The line of his hips, a couple of freckles doted on heated skin. One little freckle, all alone, right next to his nipple. Oh. Cas grabbed onto his waist, needed to touch Dean, keep him exactly where he was as he raised his hips. The nudge of Dean's cock against his hole made him groan, push down on it and let it catch on his rim. 

"You can't do this dry Cas, for the love of God-" Cas didn't stop, didn't want to hear another word about God while doing this. He dropped all the way down in one move and filled himself with Dean. The burn, the fill of it. Dean's cock bottomed all the way out in his ass, and sent shocks through him. He bit back a whine, felt like he'd just downed water after nearly dying of thirst. The pain was only for a moment, before a casual flick of his grace dealt with it. Dean's cock eased the real, deeper pain of not having, of not being filled, of not being bred like he needed. Dean groaned under a wriggle of his hips and looked up at him, with an arm thrown over his head, with irritation, spiked with lust. "You're crazy." Dean was right. Angelic heat was a form of insanity so Cas didn't argue. Couldn't with how badly he wanted it anyway, he didn't want to think of retorts, of pushing back. He just wanted his cock. He shifted, trying to push it even deeper inside him, before he moved his hips to start fucking himself on Dean's cock.

Cas had never done this like a human before. Of course he'd bred as an angel before, felt a heat before but riding Dean, feeling the catch of the head of his cock inside him, was different. There was no stretching of time and space. No spanning the galaxy as two graces merged, probing each other, exploring every nook of him, as deep and intimate as anything an angel could experience. No, it was just Dean nestled inside him, cock throbbing, eyes watching him through fluttering eyelashes like he'd never seen Cas before in his life. It was so close, so small and so human. It was a tiny gesture in a huge galaxy, and Cas wanted it so badly he would die if anything stopped them now. 

He got it. He finally grasped why so many human failings seemed to involve sex, how it could destroy men who couldn't be taken by any army. It made a terrible, clear sense as he pulled back, sliding Dean all the way out of his ass, just the tip nudging against his hole before slamming his hips back down in one swoop. It made Dean stutter, frustrated and wanting, made Dean reach out to guide his hips before Cas slapped his hands away. No. He was going to make Dean come and he didn't need Dean's guidance to do it. He'd do it his way, take care of everything, of all of his needs. All Dean needed to do was fill him up with his come.

He tightened around Dean, making Dean rise up, try to move him about again. It annoyed him. Like Dean thought he needed to be told how to be bred, like the urge wasn't consuming him, telling him everything he needed. His hands dug into Dean's hips, pinning him to the bed before he levered himself deeper, bouncing himself even harder on Dean's dick. He felt it as a spark first, a sudden brightening of Dean's soul before his body followed. Dean came inside him with a shudder that made Cas tighten his hold on his hips, digging in, bruising him as he kept fucking himself on his cock. A desperate, low noise escaped him as he felt the spurt and twitch of Dean's dick spilling inside him, filling him up with come. Not enough. Need more, more, needed to keep riding Dean until he got him knocked up, needed it so badly that the thought of not getting it was enough to make him feel like he was being pushed over an edge.

"I need more, keep going, I need more, you need to fill me, breed me, I need your baby, Dean-" It rushed out of him, breathless need into a jumble of words that Dean cut off with a hand over his mouth, brushing against his lips. Dean's face was burning as he slid out of his ass. 

"Holy shit." Quiet, awed. Maybe there was fear there too, if Cas let himself hear it. He didn't. Dean swallowed and dropped his hand. "I can't just go again, man, I'm not a teenager." Oh. That was the problem? Cas reached up, two fingers up against Dean's forehead and pushed. Dean started but Cas felt it slip in, felt his grace restoring Dean's energy. He could keep him going all night with it. Would need to keep him going until he bred him. "The hell are you doing?"

"Recharging you." It seemed obvious. He could feel Dean getting hard against his ass, enough to slide back and push his cock back inside him again in one smooth stroke. The fullness of Dean's cock filling him up made pleasure shoot up his spine. His own cock was aching but it hardly registered. Cas didn't need to come to do this, just needed Dean to come and come until it stuck, until it worked. What did Dean like, what would encourage him in their mating, encourage him to stay hard and wanting in his ass? He thought of porn, of women with lewd words. Filth that had seemed ridiculous then, that made him shudder now on Dean's dick before he even got the words out in a shameless rush. 

"I love your big cock inside me, you feel so good, I need you to come in me, I need to feel it, you're so fucking good." The words made Dean flush even redder but Cas felt his cock twitch in his ass and kept going. "I need your come, I need you to screw me until you knock me up, I need you to breed me, I need your baby, I'm yours." Dean parted his lips, red, plush, his mouth a dark mystery that Cas ached for, ached for the words to come out, but only a puff of breath did. Only that before Dean reached out and touched his dick. 

He nearly flinched off Dean's cock as his fingers wrapped around him. His warm, large hand enveloped him, his other hand pulling him back down onto his dick. Too much, too much with Dean inside him and hand on him, jerking him off. One, two, three strokes and Cas exploded.

All the lights shattered at once. Too much Dean and coming and Dean coming inside him again, to the chorus of shattering glass around them, to hold back the pulse of energy surging through him as he came in Dean's hand. His come spurting over his fist, Dean rubbing his come back over his cock to slide against his palm as he came. Kept riding Dean through it, through the burst of light behind his eyes, like he was being blinded by the lights that he'd just destroyed around them, until Dean pulled back with a hiss. Cas blinked, dazed, needed more, reached out to touch Dean and fill him with his grace to go again. For a moment he saw his own daze mirrored on Dean's face, before it switched to exasperation as he started to get hard again.

"You can't be serious." If he could think, he might be pleased to be considered capable of joking. In Cas' current state, all he could think was more, fuck, needed more, still wasn't enough, more. His vessel still shuddered from the aftermath of his orgasm but he needed more.

"I need you to breed me." His voice was rough, needy. Dean groaned, head thumping back onto the pillow again. 

"My dick's gonna break, I think I got friction burns on it." Cas reached back, looking for it like a familiar friend. He gently caressed the head, thumb running under the ridge before channeling his grace there. He needed Dean ready but Dean pulled back, pulled away from him like he wanted to stop. The thought made panic spike in him. They couldn't stop, he needed more, needing to keep pleasuring Dean until he got him pregnant. 

"Don't stop." Dean sighed before flipping Cas over. Cas fell without resistance, letting Dean pin him down onto the mattress, loom over him like he was going to give him the screwing of a lifetime. The thought made his heat burn in him, need flaring up. Dean was pinning him down. Dean was going to breed him until it took, until he was sated and filled with come and wrecked. The thought made him shudder, his cock sliding against the line of Dean's hip as he pressed down on top of him. 

"Easier to knock you up like this. You want that, right?" Cas curved up against Dean, back arching off the bed, desperation pouring off him with his breathless 'yes'. "Didn't think you were the type to talk like that. Guess you just want my dick that bad, huh?" Cas pushed up again, his ass sliding against Dean's dick, couldn't get it to press in like he wanted. The frustrated noise leaked out of him, drew a huff of laughter from Dean that made him scowl. "So badly you can't hold it back. Never had you down as wanting to be bred."

"Just do it." Dean pushed his thighs apart, Cas letting them fall around him, welcoming him in with just a hint of irritation in his need, before Dean slided himself in. His dick dragged in slow inside Cas. It wasn't like when he'd been in control, it was achingly slow and teasing instead. Cas wriggled, tried to push back onto his cock faster as he wrapped his thighs around Dean's waist. 

"Easy." Dean paused, grabbing pillows to support Cas' hips before pushing all the way into him, balls deep in Cas' ass and bottoming out. "Hold onto me, 'cause I'm about to rail you like you've never been railed before, angel." Cas groaned, grabbed onto Dean's back and held on, fingers digging in tight as Dean thrust. Easy at first, not enough, drawing noises of complaint from him until Dean sped up and started to pound into him. A shift in angle and Cas' nails dug into Dean's back, breath stuttering in his chest from it, the unexpected jolt that sent his heat into overdrive. Incoherent words fell from his lips as Dean hit it again, another jolt shuddering through him. Not quite enough but something else, something that made his cock ache and twitch against Dean's stomach, smeared pre-come on it. 

"Dean." Desperate, almost a prayer. He would pray for Dean to come in his ass if he could hear it properly. He needed it so badly, it was just the kind of thing you prayed for. 

"You like that? Talking like you've seen everything but it's so easy to overwhelm you." Even in his need, his desperation, he gave Dean a squinty, irritated look in response to Dean thinking he knew more, undermined by another jolt, as the aching shot through him. Dean didn't care, kept talking even as his breathing stuttered. "You're so good like this though. Ready to be breed, all warm and welcoming for my cock. So crazy for my dick you didn't even prep for it." Dean groaned, pounded harder into Cas as his nails scrambled across his back, cut deeper into it as Dean fucked him relentlessly. "Gonna come again."

"Please," His voice was so rough that it was almost impossible to speak. "Come in me, knock me up, please, just come, please, Dean, please," Dean hit it again and this time Cas came untouched. Lights shattered in neighboring rooms, car alarms wailed out in the parking lot as he froze under Dean, came so hard and Dean didn't stop, fucked him right through it even as his nails dug into Dean's back so hard he drew blood.

"God, you feel so good. Gonna get you pregnant like this." He felt Dean coming inside him. He dug his grace into Dean's back too as he felt himself coming undone, unraveling under Dean as his seed filled him, kept Dean hard and inside him, pounding even as he came, working so hard to knock him up, breeding him like he needed it. 

It hit him as suddenly as revelation. Dean was knocking him up. It wasn't just dirty talk. His heat made it real. Dean was a human impregnating him, an Angel of the Lord, even as he waged war in Heaven itself. It wasn't going to be new angels or new humans born from this. 

It would birth a Nephilim. Cas was creating a monster, an offense against God, committing the very oldest crime an angel could commit. The madness of his heat couldn't dull the revelation. There was no going back after this. It was beyond forgiving, more than his plans to win this war for good were. He could still feel Dean inside him, but his mind stuck on it. He was doing something unforgivable, and he didn't want to stop, couldn't stop wanting this.

Well...a Nephilim. It would be very powerful. It would be capable of defeating Raphael without Crowley's help. It would be beyond the pale, but it would be necessary to end this war, to save Heaven. A weapon to save Heaven with. 

"Cas?" Dean's hand on his face pulled him out of his head and back into what his body was doing. "You okay? You checked out." The concern on his face, even when he was balls-deep inside Cas, fucking him even when he didn't want to, made Cas feel tender. Dean was a good person, loved so much that it hurt him. That love came out in the worst possible ways sometimes but it was always love behind it, not greed or hate. He wasn't someone Cas deserved. 

"I'm fine. It's just the heat, don't stop." His hands tightened on Dean's back again, focused on Dean above him, on Dean's cock inside him. Had it already happened? He shouldn't be able to think that clearly in heat, not like that. Did he already conceive? 

Dean stopped. It took Cas a moment to realize he had, that Dean's cock was still inside him but not moving as Dean looked at him.

"I need a break."

"What - no, Dean, no, please, keep going, Dean, please-" Dean didn't listen and pulled out of him. Cas felt like he was falling as Dean's weight lifted off him, the bed creaking as he got up, scrambled back along the bed to pull on Dean's arm, to pull him back to bed. Dean staggered for a moment before pulling away. Cas dropped it. He felt the give in Dean's arm, remembered how fragile Dean was compared to him, and dropped it. His cock ached and it hurt, it hurt not to have Dean inside him, fucking him, he needed him back. 

"You completely spaced out! I'm not doing this like that." Accusatory, like Cas had done something wrong. Maybe he had, maybe he'd broken some rule he didn't know. The heat clawed at his skin as he tried to figure it out, fogging his mind up. What did he do wrong? He wanted Dean, wanted Dean to get him pregnant and Dean had agreed to. Until now. 

"Dean." The heat cracked his voice as he watched Dean open a bottle of water. His skin burned as he watched, watched Dean's throat swallow, his mouth wet and so far away. "I need you, Dean." Dean didn't stop, chugged the whole bottle of water before throwing it away, wiping the water off his lips with a swipe of his hand. 

"Yeah, you keep saying that Cas, it's been all about what you need. But what do you want?" Cas tried to parse the question. The ache in his body from not having what he needed, not being filled with cock right now was scrambling his brain. What was the difference? He needed Dean and he wanted Dean. Need and want were the same thing in this moment. Dean didn't move back to the bed as he stared at him, as Cas wetted his lips. He didn't get it but didn't want to argue the difference. So he said it, voice needing and low and yes, wanting too.

"You. I want you. I want you so badly, Dean. I want you to be the one who gets me pregnant." Dean exhaled, dropped his arms from their defensive position, crossed over his chest, to approach the bed. Cas reached, pulled Dean down on top of him with all his strength without waiting. Dean was squashing him. The weight felt perfect on top of him, drawing a groan as his cock slid against Dean's skin, thrusted up and rutted against his hip. Dean pushed back, Cas chasing air with his hips before Dean pinned him down and pulled his legs back around him again. 

"Look at me." Cas looked, meeting Dean's eyes like he had thousands of times before. Just not like this. Not with the tip of Dean's cock brushing on the edge of his rim, some of his come leaking out of his hole and making his dick slide against it. Not with the promise of more, of what he needed - wanted - so close. The silence dragged. Cas wanted to claw at his own skin, at Dean's skin to get him to do it, to push inside him. The look in Dean's eyes, searching for something, stopped him. Dean needed to look at him, and Cas let him, even if he wanted so much more. He opened himself to Dean's gaze just like he'd opened his legs for him. 

Whatever Dean was looking for, he found it. He leaned in closer. Calmer, in control, and Cas shuddered to feel his breath against his neck. "That's what you want? You want me to breed you? Get you pregnant? Fuck you until you're so full of my come that you can't take any more?"

"Yes."

"It's already leaking out of you. You sure you can handle more?" Cas let out a frustrated noise between his teeth, tried to push himself onto Dean's dick but slid past it, slipping on the come trying to escape. The ache was hurting him and burning a hole in his chest. It hurt like he was on fire and Dean was still waiting like it was nothing. 

"Dean."

"You want it?"

"Yes!"

"Tell me." Cas' patience snapped, both from the desperate need to be fucked, to be bred and from Dean testing him like this, right now. All he wanted was Dean to come in him again and again. Was it really so much to ask for? 

"I want you to fuck me and if you don't fuck me right now I will flip you over and do it _myself_." It came out in a low growl, a familiar edge of 'you are testing my patience Dean Winchester' to it. Dean took it, finally pressed the head of his cock against his hole and pushed. No teasing this time, just Dean thrusting all the way back in one movement that made Cas throw his head back, made his whole body roll as he felt Dean's cock bottom out in him again. Perfect. The pain of being empty, of not being filled abated, washed away as Dean thrusted. Easy at first before Cas grabbed onto his back again, pulled at his skin, moaned for more and Dean gave it. 

Dean pulled at his thighs, tilted the angle and pounded away inside him even harder. Cas clung on, rolled into Dean's thrusts, faster, needing more, wanting more. His body was taking the pounding like it was made for it, made to be fucked by Dean like this, destined to be fucked into oblivion, in a baby making haze and filled up with come. 

Dean found it, a thrust that hit something in Cas full on this time and Cas seized up. Oh, oh fuck. 

Dean was fucking so deep into him that he couldn't think of anything else, fingers pulling on Dean's sweaty skin, sliding on his back as he writhed on Dean's dick. Tried to pull himself off it, but Dean pinned him down and kept him flat onto the mattress as he fucked him into it. A choked sob spilled out of him. It was almost too much, too much pleasure, it was overwhelming him. His heat demanded more, to be knocked up, make the baby, forget the future, what that baby would be, just now now now, get it now. 

"Dean, please, I want," He didn't know, couldn't say it. Dean knew it anyway, pulled him in closer, fucked him harder. Cas looked up into Dean's eyes, met those beautiful green eyes looking at him with want, too, like there was a difference. He felt the brightness of Dean spilling inside him, pumping him full of his come, claiming him, making him his, and Cas came, hard and deep, seeing stars as he looked into Dean's eyes with one thought in his head as everything shattered around them. 

_I am in love with Dean Winchester._

The whole galaxy and everything in it. Every star and black hole, supernova and planet, comet and every corner where anything lived, overlayed on his human eyes watching Dean above him. Double sight. He was coming as an angel and human all at once, seeing the whole universe and yet only seeing Dean too, just as beautiful and important as the universe, maybe even more so. He felt Dean's soul bursting through to touch his grace, to tangle up in it like he was an angel, like he could read every part of him just like he'd read all of Dean while pulling him out of hell. It felt like when he'd held Dean in his grace then, but this time Dean was responsive, not afraid, not hiding. He knew him now too.

There. At the edge of his grace, in the bow wave caused by Dean's soul steaming through it like he charged into everything. There it was, the moment of conception. He could feel it. The terrible, awesome love spinning inside him and its consequences. The Nephilim now inside him, both in his grace and his body. Trailing in the wake of Dean racing through his grace and settling into his human body. 

He was in love with Dean Winchester and that was why he came here. Not out of practicality, from not having any other choice, from wanting a more powerful weapon. He just wanted Dean, wanted all of him. He wanted this without any care for the consequences. 

He'd known for so long. He'd known for so long without knowing it himself. The difference between loving someone and being in love with them, that he'd denied for so long, blinded himself to. Now, with his eyes opened, Dean's soul in his grace and the cascade of love it caused inside him, he could never close them again.

"Cas?" He heard the fear in Dean's voice as the galaxy faded from before his eyes, as he felt Dean's soul withdraw from his grace. As he came down with a bump, suddenly back in his vessel with wetness on his face. He'd cried? Unexpected. He wiped it away before reaching up, pulling Dean against his chest and his fingers moving into Dean's hair. He felt the fear in Dean too, tried to ease it even as he wondered if Dean could understand what had just happened to his soul, that it hadn't just been his seed Cas needed.

"Thank you, Dean." He felt Dean relax in his arms. He meant it. He was overwhelmed and awed. Something else was there too. Happiness. In the moment he felt a happiness he knew he would never get to feel again. He could feel the echo of Dean in his grace, the heat and wetness of Dean's come inside him, the angel and human breeding tangling up together. He was holding Dean in his arms and knew he would never do it again after today. He held Dean and Dean let him, sunk into his embrace as he shut his eyes. Head pillowed on his chest, hair brushing against his neck as he worked his fingers through it to calm it. It was beautiful, a sight that made love swell inside Cas.

For a minute he had it. Pure, unrestrained happiness, before Dean let out a sigh and pushed himself up. 

"Ugh, give me five and I'll be back. Need a human break." Despite the threat of Dean getting up, leaving for a moment, Cas didn't feel the blind panic of earlier. Didn't feel like he was about to die because Dean paused in fucking him. Instead he felt himself smile at the need for a 'human break'. That was it, his heat was done. He must only be able to handle one baby in this vessel, then. Despite his words Dean didn't rush up, trailed his hand along Cas' chest, running down his body before lingering on his hips for a moment. Cas let him linger, he would let Dean take as long as he wanted, but Dean finally pulled himself up and out of bed. Carefully Dean picked his way through the broken glass to the bathroom, moving like it was a trap he'd set to capture Dean but he'd never be caught by.

The promise of more lingered in the air. Dean wasn't rushing away, was only taking a break and expecting Cas to still be in bed, waiting for him when he came back. Cas wanted it, wanted more. Even with his heat finishing, he could keep going. He wanted to keep going, to stay the night with Dean and fuck until dawn, until Dean finally collapsed in exhaustion. To lie by Dean when he slept, to watch over him until he woke up, then go to get breakfast together when he did. To watch Dean eat with that ache in his chest it always gave him to see Dean eating, to see him happy, while his coffee was neglected in front of him, while Dean ripped on Sam for whatever choice he'd made for his breakfast.

The Nephilim tugged on his grace. He couldn't stay, it was too dangerous. He'd already asked Dean for too much. He shouldn't have asked for this, couldn't ask for even more. Dean had no idea what he'd just borne, of Cas' love for him or the abomination Cas was now carrying. 

Sam would have known and Cas was grateful, so grateful, that he wasn't present right now, that Dean wouldn't talk to his brother about this. Sam knew much more about angels, he knew the lore. He'd know about Nephilim, about how forbidden they were, that a human could get an angel pregnant. Dean didn't. He thought it was just dirty talk, something that Cas was into.

It was a betrayal. He'd realized it too late, but it was. He'd betrayed Dean, who trusted him, even when he shouldn't have. Misled him into thinking this was less than it was, was more than it could ever be. He would have to live with that too.

With a swish of his hand, Cas cleared the glass away, restoring it back to where it belonged. In the distance, he felt the aftershock following a larger earthquake, and heard the silence from the absence of the hum of electricity. Of car alarms still wailing in the distance. Reached out and felt the shattered glass, all the broken, blown out lights in a hundred mile radius. He pushed out further, saw he'd knocked out the power grids for both North and South Dakota and caused an earthquake nowhere near a fault-line. It would not go unnoticed. Heaven would know exactly what these signs meant. 

He had to go now. He cleaned himself up, reluctant to sweep away the evidence of this occasion, of just how successfully Dean had knocked him up. He left the come inside him, wanted to feel it, to know that this had really happened. Even if it was something that he knew he couldn't keep if he was to win this war. He pulled his clothes back on as he heard Dean moving around in the bathroom. If he didn't go now, before Dean came back out, Dean would ask him to stay. He would say yes and rain Heaven's wrath upon both of them. He knew he couldn't say no to Dean, and that he couldn't let himself say yes. He reached the door, wiped the sigil off it before vanishing just as Dean opened the bathroom door. Cas knew how Dean would react, how angry he'd be, and made his own prayer to him as he threw himself out of Dean's orbit and out of his galaxy altogether. 

'I'm sorry, Dean. This was too much to put on you. I must bear it alone.' 

Not entirely alone. He felt the roll inside him, felt it growing inside him. His final weapon to win this war. After doing something unforgivable, he could at least use the results of it. It was always thus. A warrior must fight with whatever weapons they had. Raphael, unintentionally, gave him this, and he would use it to destroy him. 

Dean wouldn't approve. It was another betrayal. Dean would want it to have a chance, to let it live as a human, to be more than this, than a weapon for its father. A weapon for Castiel just like Castiel was a weapon for God, just like Dean was a weapon for John Winchester. The Dean in Castiel's head asked him what the fuck he thought was doing. Something important, he told him. This war must be won, and everything must be used to win it. He felt it stir in his grace, curious already about its parents, about the angel already making plans for its future. 

_Everything?_

Yes. Everything. Even that love at the very center of his grace. Everything.


End file.
